The present invention relates to controlled motion systems and more particularly, to controlled motion systems capable of independently controlling multiple movers on a track.
Systems incorporating linear motor sections that provide independent control of multiple moving elements have been used in a wide variety of processes (e.g. packaging, assembly automation, processes involving use of machine tools, etc.) and provide the advantage of increasing both the speed and flexibility of the process. Since linear motors employ a moving magnetic field to directly drive the moving element (hereinafter referred to as “movers”), they eliminate or reduce the gear heads, shafts, keys, sprockets, chains and belts often used with traditional rotary motor systems. This reduction of mechanical complexity provides both reduced cost and increased speed capability by virtue of reduced inertia, compliance, damping, friction and wear. This technology also provides greater flexibility than pure rotary motor systems by allowing each individual moving element and its associated tool or payload to be independently servo-controlled along a portion of its path.
Such Systems often comprise both “smart” sections which can independently control the motion of each mover on the section and “simple” sections which drive each mover at the same speed on that section. These simple sections typically employ a rotary axis that drives movers with either a magnetic or mechanical coupling to the mover.
One problem with prior art systems is that it is often difficult to know the position of a mover as it travels along both the smart sections and the simple sections. Further, it is often difficult to speed up or slow down movers as they travel along the entire track as well as changing the pitch (or distance) between movers as they move along the simple sections.
Accordingly, a need exists for a controlled motion system having at least one smart section and at least one simple section, that operates to allow movers to be controlled as they travel along both smart and simple sections, that allows the speed of a mover to increase or decrease as it travels along a simple section, and allows the pitch or distance between movers to increase or decrease as they travel along a simple section.